A virtual machine control apparatus that implements a plurality of virtual machines operating independently of one another is a known art. For example, Patent Literature 1 discloses an OS (Operating System) switching apparatus, which is one example of the above type of virtual machine control apparatus.
In a situation where the plurality of virtual machines operating independently of one another share use of a device, when more than one of the virtual machines performs an operation to control the device, a race condition for control of the device occurs therebetween, and consequently there is a possibility that the device cannot be used correctly.
Therefore, in a situation such as described above, generally only one of the virtual machines (referred to below as virtual machine A) has a device control unit for controlling the device. When any of the other virtual machines is to use the device, the other virtual machine uses the device by requesting the virtual machine A to control the device.